Grindstone mold



March 10, 1936. E. MARX 2,033,249

GRINDSTGNE MOLD Filed Nov. `le, 1933 Patented Mar. l0, 1936 STATES rar ori-ice implication November 16, 1933, Serial No.,698,249

In Germany May 5, 1933 2 Claims.

The invention relates to the manufacture of grinding tools, in particular cylinder honing tools as described in my Patent No. 1,918,852, and its object is to provide a new mold for securing the 5 stones in the jaws or mountings in which they are supported, by which a better grip of the mounting upon the stone is obtained and breaking out thereof avoided.

According to the present invention, the stone is held by the mold in its definitive position, in relation to the mounting, and a setting uid binder is then forced under pressure into the space between the stone and the mounting. By

introducing the uid, which can consist for example of molten lead, tin or the' like, or an alloy of similar character, under pressure, some of it is forced into the pores of that part of the stone lying between the side walls of the mounting, thus ensuring a rm and lasting connection between the stone and the binder. It is then impossible for the stone to break out of the mounting. Even if a stone cracks through, the pieces cannot come loose but remain in position in the binder so that a cracked stone can continue in use. 1n accordance with the present invention, furthermore, it is possible to make the side walls of the mounting lower, or in other words to reduce the depth of insertion of the stone into the mounting so that a greater portion of the stone projects from the mounting and the stone can thus be used till worn down to a greater extent. Accordingly the life of the grinding tools is increased.

In the accompanying drawing, Figures 1 and 2 respectively show the two halves of the mold in front view;

Figures 3 and 4 are cross sections of the mold halves, taken on the line III- III of Figure 1 and IV-IV of Figure 2 respectively;

Figure 5 is a cross section of the closed mold with the mounting and stone in position, on the line V-V of Figures 1 and 2, on an enlarged scale;

Figure 6 is a side view of the casting apparatus;

Figure 7 is a detail view of the operating mechanism on an enlarged scale; and

Figure 8 is a longitudinal section through the heatable container for the binder, with an incorporated pressure cylinder.

The invention comprises a two part mold I, 2, of which one half I has a groove 5 in which ts a substantially U-shaped mounting 3 for a honing stone 4. From the groove 5 three bores 6,

l, and 8 extend through the wah ofthe mold half I, of which the two outer 5, 'I serve to receive guide pins 9 and I0 projecting beyond the mounting 3. These guide pins 9, Ill pass through the floor of the mounting 3 and project a certain amount therein. The counter-half 2 has 5 a recess I3 adapted to receive the projecting side walls II, I2 of the mounting 3 and a groove I4 to receive the honing stone d.

The two mold halves I and 2 are provided with passages I6 and Il respectively which serve 10 for circulation of a cooling medium, and are connected to pipestherefor, for example water pipes, by connections It, I9 and 2t, 2i respectively. At the narrow end of the mold halves opposite to those in which the connections I8, i9 15 and 20, 2i are provided, semi-conical grooves 22, l 23 extend outwardly from the groove 5 and re cess I3 respectively, which `when the mold is closed form an inlet duct of funnel form for the uid binder. To ensure correct relative posi- 20 tion of the mold halves when closed, the halves I, 2 are provided with projecting dowels 2t, 25 respectively. These dowels 2B, 25 lie on a, diagonal and when the mold is closed enter corresponding recesses 26, 21. 25

To carry out the' new process the mounting 3 is placed in the groove 5 of the mold half I and the honing stone 4 is placed in the recess It in the other half 2. The two halves are then assembled and the mold thus closed (Figure 5) 30 The guide pins 9, I0 projecting on the inside of the mounting 3 support the honing stone 4 and maintain its position relative to the mounting. The mounting 3 is prevented from displacement by the engagement of its side walls II, I2 in the 35 groove I3. The uid binder-say a. molten tin alloyis now introduced under pressure through the inlet funnel 22, 23. This fills the hollow space in the mold and some is also forced into the pores of the honing stone, so that a firm and lastingv 40 connection between the latter and the mounting is produced.

As Figure 5 shows, the honing stone is only overlapped by the side walls of mounting 3 by a small fraction of its total height. But this small 45 depth of entry suiiices when the new mold is used to ensure a thorough grip of the stone. The introduction of the binder under pressure into the mold is effected by the apparatus shown in Figures 6-8. 50

.The two plates 3|, 34 connected by parallel bars 32, 33 are swingably mounted upon a base plate 28 by pins 29 carried in bearing brackets 30. The mold half I is secured to the plate 3l by stationary supports `35, 36. The plate 3| further 55 carries in a guide 31 a rod 38 which can be thrust towards the mold half I by a hand lever.39. When so thrust forward the rod 38 enters the central bore 8 in the mold half I and then pushes the mounting 3 out of the mold half. A yoke 40 coupled to a lever arm 42 by a link 4I is slidable upon the rods 32, 33. The lever arm 42 is pivoted upon the plate 34 and has a handle 43. The yoke 40 carries the mold half 2 by supports 44 that are movable with said yoke. Between the plate 34 and the yoke 40 a rod 46 is arranged upon a bracket 45 supported by the plate 34,

, which rod passes through a hole in the yoke 40 and carries on its end a cross piece 41 with six projecting pins 48. 'Ihese pins 48 are arranged in such a manner that when the yoke 40 is moved towards the plate 34 they enter holes I5 in the mold half 2 and push the mounting out of the mold half 2 which process is carried out after the casting operation. A spring 49 upon the rod 46 serves to hold the mold I, 2 closed. 'Ihe parts 3|, 32, 33, 34 may be rotated around the pins 29 by an operating lever 50 articulated to the plate 3| and pivoted to the frame 28 of the apparatus at 5 I. To one side of the rotatable moldcarrying frame formed by the parts 3|, 32, 33, 34 there is arranged an operating shaft 53 borne in a. bearing 52, which can be rotated from a hand crank 56 through toothed wheels 54, 55. The operating shaft 53 carries a drum 58 with a helical cam groove 51, and also a cam disc 59.' The operating lever 50 engages the helical groove 51 of the drum 58 and is thereby oscillated to swing the frame 3|, 32, 33, 34.

A container 6I (Figure 8) for the binder stands upon the base plate 28 behind the swingable frame 3|, 32, 33, 34. 'Ihe container 6I open at the top can be heated by a. burner 62 located beneath it and contains a cylinder 63 in which works a piston 64. The cylinder is connected with the container 6| by apertures 65 and with an outlet nozzle 61 on the outside of the container by a duct 66. The piston 64 is mounted on a carrying lever 68 which is pivoted upon a standard 69 on the base plate 28 and bears with a roller 10 against the cam disc 59. A spring actuated/pull rod 1I attached to the carrying lever 68 ensures contact between the roller 10 and cam disc 59, one end of the spring 12 bearing against the base plate 28 and the other end acting downwardly on the rod 1I.

The apparatus operates as follows:-

After the mounting 3 has been placed in the mold half I and the honing stone 4 in the half 2, the mold is closed by moving the handle 63, the yoke 40 moving to the left in Figure 6. 'I'hen by rotating the hand crank 56 the frame 3|, 32,

33, 34 is swung inwards by the lever 50 actuated by the cam groove 51 in the drum 58, until the inlet funnel 22, 23 of the mold I, 2 bears against the outlet nozzle 61. While the drum 5B is rotating, the 4cam disc 59 is also rotated in such a manner that as soon as the funnel 22, 23 bears firmly against nozzle 61, the carrying lever 68 rises and thus thrusts the piston 64 downwards in the cylinder 63. The piston 64 in its movement shuts off the apertures and then drives the fluid binder trapped in the cylinder 63 through the nozzle 61 into the mold.

After completion of the casting operation, the piston 64 is raised in the cylinder 63 by reversing the rotation of the crank 56 so that the apertures 65 are uncovered and further uid binder can ilow into the cylinder. At the same time the mold is moved away from the nozzle 61. The mold is then opened by actuation of the handle 43 and lever arm 42. In order that the honing stone 4 secured in the mounting 3 may not stick in the mold half 2, the pins 48 enter the holes I5 when the mold halves I, 2 are separated and push the mounting 3 with the stone 4 out of the half 2. If however the completed tool 3, 4 sticks in the mold half I, it can be pushed out by thrusting forward the rod 38 by means of the hand lever 39.

Modifications may be made by persons skilled in the art within the spirit of the invention, and

all such are lconsidered to be embodied within the scope of the appended claims.

What I claim is:-

1. A mold for securing a honing stone in a mounting by means of a setting binder, comprising two mold halves each having passages for a cooling medium and of which one has a suitable groove for receiving the mounting and bores adapted to receive pins carrying the mounting while the other mold half is provided with a recess for receiving the honing stone.

2. A mold for securing a honing stone in a mounting by means of a setting binder, comprising two mold halves each having passages for a cooling medium and of which one has a suitable groove for receiving the mounting, bores adapted to receive pins carrying the mounting and a. bore for the entry of a pushing out rod, while the other mold half has a recess for receiving the honing stone and adjacent thereto holes into which pins can enter the ends of which will abut the side walls of the mounting, the abutting faces of said mold halves having grooves therein which together form an inlet duct for the binder.

ERICH MARX. 

